ZZZZZZ

Here's how you do it:

7.5 + 6.21 = 13.71

13.71 * 15 = 137.1 + 68.6 = 212.7

212.7 is the answer. 

(I did the math in my head, so just in case put it in the calculator)

13%. It says in the key.

There are many ways, but you can use distribution. It may not be the easiest, but I find it easier to do it this way unless I use a calculator.

(1+0.15)(3+0.2)

First, do 1*3 and 1*0.2

You get 3 and 0.2 which added equals 3.2

Then do 0.15*3 and 0.15*0.2

You get 0.45 and 0.03 which added equals 0.48

Add those together and get 3.68.

if you're finding arc measure of minor arc HJ, 360-281 also equals 79 degrees.

arc measure, arc length, or distance apart?

a bit is one-eigth of a byte.

explain why you don't understand it.

I'm not cheating, I call it using my resources wisely, and I've only done that a couple times.

It's a basic quadratic function.

step1:  ax²+bx+c = 0

It takes a while, but you eventually get to the quadratic formula, x=(-b ± sqrt(b²-4ac)/2a

Also, is there a plus/minus button? I just copied the symbol I used off Google.